put in an auto* check for the path to perl (if it exists), and modified

* configure.in, Makefile.am: put in an auto* check for the
  path to perl (if it exists), and modified make Timingtests
  to use that path instead of just executing the dbgenattr.pl
  script (bug 148056)
diff --git a/configure.in b/configure.in
index 52f0af2..9c86650 100644
--- a/configure.in
+++ b/configure.in
@@ -31,6 +31,7 @@
 AC_PATH_PROG(RM, rm, /bin/rm)
 AC_PATH_PROG(MV, mv, /bin/mv)
 AC_PATH_PROG(TAR, tar, /bin/tar)
+AC_PATH_PROG(PERL, perl, /usr/bin/perl)
 
 dnl Make sure we have an ANSI compiler
 AM_C_PROTOTYPES